Cross-coupling gate contact structures are important for standard cell design to achieve product area scaling goals of advanced technology nodes. However, as technology advances (e.g., 14 nm technology nodes and beyond), it may be difficult to construct a cross-coupling gate structure within a two-gate pitch region using traditional methods.
FIG. 1 schematically illustrates a typical cross-coupling-based design. As shown, the design in FIG. 1 includes gate structures 101 over one or more diffusion regions 103 having one or more diffusion contact structures 105, gate contact structures 107 (gate contact structures 107a through 107c) over gate structures 101, and via structures 109 (e.g., via0) to couple some of the gate contact structures 107 to the metal routing layer (e.g., metal1 routing layer) (not shown for illustrative convenience). To separate gate contact structures 107, portions of some of the gate structures 101 are cut by gate cut regions 111. As illustrated, the design in FIG. 1 utilizes two gate cut regions 111 and one straight gate contact structure 107 over two gate structures 101 to achieve the cross-coupling-based design. Based on this design, for instance, for 20 nm technology nodes, two-gate pitch region 113 (which encompasses the gate contact structures 107) may be 140 nm to 200 nm in width (e.g., indicator 115) and 200 nm to 230 nm in length (e.g., indicator 117).
FIG. 2 schematically illustrates another cross-coupling-based design. As shown, the design in FIG. 2 similarly includes gate structures 201 over one or more diffusion regions 203 having one or more diffusion contact structures 205, gate contact structures 207 (e.g., gate contact structures 207a through 207d) over gate structures 201, and via structures 209 to couple some of the gate contact structures 207 to the metal routing layer (not shown for illustrative convenience). As depicted, the design in FIG. 2 utilizes one gate cut region 211 to separate the gate contact structures 207 (as opposed to using two gate cut regions 111 for the design in FIG. 1), and diffusion contact structure 213 to couple gate contact structure 207b on one gate structure 201 on one side of the gate cut region 211 to gate contact structure 207c on another gate structure 201 on the opposite side of the gate cut region 211. In this example, two-gate pitch region 215 may, for instance, be 140 nm to 200 nm in width (e.g., indicator 217) and 300 nm in length (e.g., indicator 219).
As technology advances, the designs in FIGS. 1 and 2 may result in low diffusion efficiency, for instance, due to the lengths of the two-gate pitch regions 113 and 215. Consequently, this low diffusion efficiency reduces the drive strength of the standard cell, negatively impacting its performance. In addition, the complicated gate contact structures in FIGS. 1 and 2 (e.g., complicated with respect to patterning) may impose yield or reliability concerns as technology advances as a result of shorter spacing between adjacent gate structures.
A need therefore exists for more effective and efficient cross-coupling-based designs, such as designs utilizing diffusion contact structures for cross-coupling, and enabling methodology.